Track switches or turnouts are found at various locations along railroad or railway tracks that typically include one or more switching rails that are movable relative to fixed track rails between one position that allows a train or cars of the train to continue traveling along the same set of tracks or another position that switches the train or cars of the train to another set of tracks. Since they are automatically or remotely activated, it is very important to keep them free and clear of any obstructions, including ice and snow, which could interfere with their operation. Switch clearing systems are commonly employed to prevent the buildup of snow and ice along track switches so they remain operable. Proper switch clearing system operation is therefore critical to ensure ice and snow accumulation does not interfere with the ability of each switching rail to be moved when the switch or turnout is activated.
Switch clearing systems come in many forms, including those which use fluid, e.g., heated air, as well as electrical heating elements to clear away snow and ice so it does not interfere with switch operation. One commonly used type of switch clearing system is disclosed in U.S. Pat. Nos. 3,972,497; 4,695,017; and 6,065,721, which directs air through ductwork, tubes and/or shrouds out nozzles or other orifices directing streams or curtains of air at relatively high velocity toward the rails of a switch to help keep them clear. These and other lower velocity systems can employ burners or heaters, such as those that use a combustible fuel, such as natural gas, propane, or the like, to heat up the air before it is discharged against the rails in the vicinity of the switch.
Another commonly used type of switch clearing system employs a switch or rail heater of the type taught by U.S. Pat. Nos. 3,974,993 and 5,824,997, which uses one or more heating elements that can be electrically powered to heat up or defrost rails, including switching rails, and other components of a switch to help keep them free of snow and ice. With rail heaters, one or more heating elements typically are in direct contact with a corresponding rail to melt snow and ice accumulation and prevent buildup of snow and ice.
While switch clearing systems are in widespread use, they are not foolproof. Since they use so much energy when operating, they typically utilize a control system that interfaces with one or more sensors, such as capacitive sensors, temperature sensors, precipitation gauges, and the like, to control when they operate. There are times however, when the control system can malfunction, such as when a precipitation gauge malfunctions during periods of high winds or excessive precipitation accumulation. There are times when weather conditions are so extreme that snow and ice buildup despite switch clearing system operation.
It has long been known to supplement them with barrier systems, such as disclosed in U.S. Pat. Nos. 4,671,475; 5,018,690 and 6,571,963, which work in concert with switch clearing systems to increase their effectiveness. Such barrier systems typically utilize tarpaulin, waterproofed canvas, wooden boards, and fiberglass covers adjacent part of the switch clearing system to not only help provide shielding but also to attempt to reduce heat loss.
Unfortunately, these conventional barrier systems possess many drawbacks. Since their barriers are of solid, imperforate or hard shell construction, they cannot be placed too close to the top or head of any rail to avoid directly contacting part of a train or rail maintenance vehicle traveling on the rails, which can significantly limit their effectiveness. For example, road-rail maintenance trucks capable of legal use on road and railway tracks, also known as “highrailers” or hi-rail trucks, have flanged metal wheels that lower onto the rails to guide the truck whose tires ride directly on the rails. Many of these trucks have dually rear tires with the outer tire hanging down alongside the outer rail. The tires of such a rail maintenance vehicle can come into contact with barriers as the vehicle travels along the rails, which can dislodge or even damage them. The same can occur with chained together semi-trailers riding on bogies or wheelsets in a “roadrailer” configuration being pulled by a locomotive that have tires that hang downwardly very close to the rails, as this also limits how high and how close to the rails that conventional barriers can be located.
In addition, high winds combined with the repeated cycling caused by the wash from trains passing through also can dislodge and even damage such barriers, which not only can adversely impact switch clearing system operation, it can also undesirably result in a dislodged or damaged barrier coming into contact with part of the train at some point further damaging or even destroying them. To prevent these things from happening, conventional barriers are spaced far enough from the top or head of the rail so that directed contact is avoided and so the impact on them from train wash is negligible. Unfortunately, the large spacing that must be provided results in considerable heat produced by rail heater operation being lost dramatically reducing the effectiveness of these types of switch clearing systems, particularly in severe or extreme weather conditions.
Conventional barrier systems suffer from other drawbacks as well. Despite being so far away from the top of any rail that rail heater heat loss cannot be prevented, such barriers are usually still located close enough to hinder track inspection and repair. Where inspection or repair is required, removal is undesirably time consuming and labor intensive. In some instances, their use is seasonal requiring them to be removed and typically stored in large, space consuming racks. Accordingly, it has been found that locations utilizing these types of barrier systems have relatively high operating and maintenance costs.
One type of system that has been developed that seeks to overcome at least some of these drawbacks is a vertical brush strip arrangement disclosed in WO/2005/103384. While the vertical brush strip arrangement disclosed in WO '384 has enjoyed considerable commercial success in Europe, improvements nonetheless remain desirable. Though conducive for rail inspection, its perpendicular vertical orientation and large distance from the adjacent rail allows snow and ice accumulation to occur between the brush strip and rail limiting its functionality as a barrier system. In addition to the large gap between the brush strip and rail allowing falling snow to accumulate, the gap also allows wind flowing generally perpendicular to the rails, particularly at relatively low velocities, to blow snow over the brush strip into the gap between the brush and rail which also can cause accumulation to occur. Finally, the spacing is so great from the rail that the brush strip does nothing to prevent heat loss during rail heater operation.
It therefore would be desirable to provide a barrier system for railway tracks which better protects areas along the railway tracks where switch clearing systems are located and which does not suffer from the foregoing described disadvantages.